Everyday commands

The commands you use most on a Linux command line, as they work in Ubuntu Terminal. Type helpme in the app for a short version of this page.

Files and folders

Command	Example	What it does
pwd	pwd	Prints the folder you are in
ls	ls	Lists files, in colour
ll	ll	Long list with details and hidden files (ls -alF)
la	la	Lists hidden files too (ls -A)
l	l	Compact list with type markers (ls -CF)
cd	cd Documents	Changes folder
mkdir	mkdir my-app	Creates a folder
touch	touch notes.txt	Creates an empty file
cp	cp a.txt b.txt	Copies a file
mv	mv old.txt new.txt	Moves or renames
rm	rm file.txt	Deletes a file
rm -rf	rm -rf folder/	Deletes a folder and everything in it

DANGER

rm and rm -rf delete permanently. Nothing goes to the Recycle Bin. rm -rf does not ask for confirmation.

To copy a folder with its contents, add -r: cp -r project project-copy.

Move around faster

Type	To go
cd or ~	To your user folder
..	Up one level
...	Up two levels
cd -	Back to the folder you were in before

~ at the start of a path means your user folder, so ~/Documents is your Documents folder.

Names with spaces need quotes: cd "My Projects".

Look inside files

Command	Example	What it does
cat	cat notes.txt	Prints the whole file
head	head -n 20 log.txt	Prints the first lines
tail	tail -n 20 log.txt	Prints the last lines
less	less log.txt	Opens a pager. Arrow keys scroll, /word searches, q quits
more	more log.txt	A simpler pager
wc	wc -l log.txt	Counts lines, words and characters

Search and process text

Command	Example	What it does
grep	grep -i error log.txt	Prints lines that contain a word. Matches are coloured
find	find . -name "*.txt"	Finds files by name, below the current folder
sort	sort names.txt	Sorts lines
uniq	sort names.txt | uniq	Removes repeated lines next to each other
sed	sed 's/old/new/g' file.txt	Replaces text as it prints
awk	awk '{print $1}' file.txt	Prints chosen columns

Combine commands

Pipes and redirects work as on Linux.

Symbol	Example	What it does
|	ls | grep txt	Sends the output of one command to the next
>	ls > files.txt	Writes output to a file, replacing its contents
>>	echo done >> log.txt	Adds output to the end of a file
<	sort < names.txt	Reads input from a file

A worked example: count how many lines in a log mention "error", ignoring upper and lower case.

grep -i error app.log | wc -l

Clear the screen and stop a command

To do this	Use
Clear the screen	clear or cls
Stop a running command	Ctrl + C
Bring back earlier commands	Up and down arrows
Complete a name	Tab
Close the shell	exit

Get help on a command

Most commands print their options when you add --help:

grep --help

The commands come from BusyBox, a compact toolkit. They cover the common options, but a few rarely used options from full Linux systems are missing. If an option from a tutorial is rejected, check --help for what is supported.

Next steps

• Edit files with vi
• Use Git
• Run Windows programs and agent tools